The present invention relates to an information recording processing apparatus, an information reproduction processing apparatus, an information recording medium, an information recording processing method, an information reproduction processing method, and a computer program, and more particularly to an information recording processing apparatus, an information reproduction processing apparatus, an information recording medium, an information recording processing method, an information reproduction processing method, and a computer program by which a cryptographic key, such as a copy protection key, is recorded in a form in which it is difficult to analyze on an information recording medium on which contents such as, for example, image data and music data are recorded and can be reproduced efficiently from the information recording medium.
When data, such as music data or image data, is recorded as digital data on a recording medium, a recording process in accordance with a predetermined recording format is performed. For example, error detection/correction codes are added to original data of an object of recording and converted (encoded) into data of a format conforming to a particular data recording/reproduction process and then recorded.
As an information recording system which allows high density recording of information (for example, a DVD (Digital Versatile Disc) system or a Blu-Ray Disc system which uses a blue laser, whose development has been and is proceeding in recent years, to record or reproduce information) is available.
Contents to be recorded on such information recording media as mentioned above include, for example, cinema data and music data. With regard to most contents, such as music data and image data, the distribution right or the like is usually owned by a preparing person or a selling person. Accordingly, upon distribution of such contents, it is usually the case to adopt some fixed utilization control; that is, a measure for permitting only a legal user to utilize the contents but inhibiting duplication or the like which is not permitted.
A large capacity recording medium, such as a recording medium to which a blue laser recording system which allows high capacity recording is applied, allows recording of data; for example, for one or several cinemas. Contents can be recorded as digital information which does not suffer from degradation in copying and reproduction processes, this giving rise to the occurrence of many problems of a flood of illegal copies. Thus, the problem of an obstruction of benefit to the owner of the copyright or the right of distribution of contents is getting serious. From such an existing state of things as just described, it is a significant subject how to prevent illegal copying and assure protection of benefit of the owner of the copyright or the owner of the right of distribution.
In order to prevent such illegal utilization of contents, it has been proposed to record contents, which are to be recorded on an information recording medium, as encrypted contents and record additional information such as copy protection key information as cryptographic key information to be applied in utilization of such encrypted contents, information necessary for generation of a cryptographic key, or various kinds of control information such as, for example, for reproduction control or copy control of the contents as secret information on the information recording medium. A reproduction processing program to be executed on a reproduction apparatus of a user causes the reproduction apparatus to read the secret information, such as a key corresponding to contents of an object of reproduction, decode the contents in accordance with the read secret information and execute utilization of the contents in accordance with reproduction control information.
An apparatus for embedding particular information, such as a cryptographic key, is disclosed, for example, in Japanese Patent Laid-Open No. 2002-93058 (hereinafter referred to as Patent Document 1). The Patent Document 1 discloses a configuration for placing secret information into scrambled data.
While various proposals have been made for a configuration for storing additional information, such as cryptographic key information, a technique for analyzing such additional information also has progressed. Thus, the present condition is such that information regarding at what place of an information recording medium and in what manner information is recorded is acquired by a user or an illegal contents user, by whom leakage or falsification of additional information or illegal copying of contents is performed. As a result, the form of utilization of contents based on the legal right of utilization of contents is damaged, resulting in a problem that sufficient protection of the copyright or the right of utilization of contents is not achieved.